Tacos and Happy Hour, With Untraditional Fillings

Chef Alex Garcia has more than a few culinary colleagues who specialize in Mexican fare. "I have tons of friends," he said. "I invited them to join me and we called the restaurant Amigos."

Guest chefs, including Aaron Sanchez, Adrian Leon and Roberto Santibanez, are invited to create special menus for the restaurant, which remain on the menu for a month. Amigos, near Columbia University, is just one of Mr....